Pediatric Nutrition and TPN Management
Babies who don't eat well get infections. They have prolonged ventilator weaning. Their wounds don't heal. But you can also overfeed them into hyperglycemia and make CO2 production so high that they can't breathe. Get it right.
Caloric Requirements by Age
Infants have the highest energy requirements per kilogram:
- 0–6 months: 100–120 kcal/kg/day (approximately 500–600 kcal/day total)
- 6–12 months: 80–100 kcal/kg/day (approximately 700–850 kcal/day total)
Preterm infants need 110–130 kcal/kg/day for catch-up growth. They're small but growing fast.
Toddlers (1–3 years): 80–100 kcal/kg/day
Preschool (4–6 years): 70–90 kcal/kg/day
School-age (7–12 years): 55–75 kcal/kg/day
Adolescents: 40–55 kcal/kg/day
Sick kids: 1.2–1.5× their baseline. Sepsis, trauma, or major burns may require 1.5–2×.
Use WHO Calories to figure out your target.
Schofield BMR: For the Detail-Oriented
If you want to get fancy with it, use Schofield to calculate actual metabolic rate:
Males 3–10 years: BMR (kcal/day) = 22.7 × weight (kg) + 495 Males 10–18 years: BMR (kcal/day) = 17.5 × weight (kg) + 651 Females 3–10 years: BMR (kcal/day) = 22.5 × weight (kg) + 499 Females 10–18 years: BMR (kcal/day) = 12.2 × weight (kg) + 746
Then multiply by activity factor (1.3–1.5 for sick kids) and injury factor (1.0–1.5 if they're running a fever or in sepsis).
Use Schofield BMR.
TPN Macronutrients
Protein: Infants need the most:
- 0–6 months: 2.5–3 g/kg/day
- 6–12 months: 2–2.5 g/kg/day
- Toddlers: 1.5–2 g/kg/day
- Older kids: 1–1.5 g/kg/day
- Sick kids: 1.5–2 g/kg/day
- Renal failure: Back off to 0.8–1 g/kg/day
Don't start high on day 1. Creep up: start 0.5–1 g/kg/day and advance by 0.5–1 g/kg/day daily until you hit goal by day 3–4.
Dextrose (it's 3.4 kcal per gram):
- Newborn day 1: 4–6 g/kg/day (prevent hypoglycemia)
- Day 2–3: 8–10 g/kg/day
- Day 4+: 10–14 g/kg/day (keep it ≤12–14 or you'll cause hyperglycemia)
- Older kids: 5–10 g/kg/day, go up gradually
Anything >12.5% needs a central line.
Lipids (9 kcal per gram):
- Start: 0.5–1 g/kg/day
- Advance: Add 0.5–1 g/kg/day each day
- Goal: 2–3 g/kg/day (neonates can go to 4 g/kg/day)
Run it over 12–24 hours to avoid high triglycerides. Check triglycerides weekly if you're doing >3 g/kg/day. Stable kids can do cyclic lipids (8–12 hours).
Use TPN Macros.
Glucose Infusion Rate: For Neonates
GIR tells you how much glucose you're actually pushing per minute:
GIR = (g dextrose/kg/day) / 1.44
The targets:
- 2–4 mg/kg/min: Early support
- 4–7 mg/kg/min: Standard for preterm babies
- 7–12 mg/kg/min: Full nutrition for growing preterms
- >12 mg/kg/min: You're going to cause problems
Why? GIR >12–14 flips you into lipogenesis (making fat from carbs). Liver gets steatotic. CO₂ production shoots up. Now the baby can't wean off the vent.
Use GIR to calculate.
Breast Milk Fortification
Mature breast milk provides approximately 65–70 kcal/100 mL (about 20 kcal/oz). Preterm babies need approximately 80 kcal/100 mL (24 kcal/oz) for adequate growth.
Powder fortifiers add about 4 kcal/100 mL. Liquid ones are more flexible. Modular fortifiers let you customize protein, fat, carbs when standard ones don't work.
Target weight gain for preterm infants is 15–20 g/kg/day. If you're not hitting that, increase fortification or consider supplemental feeds.
What You Actually Monitor
- Use WHO or Schofield to set calorie targets
- Ramp up TPN slowly, babies don't tolerate jumps
- Target blood glucose 60–150 mg/dL in neonates (glucose >150–180 mg/dL may warrant reducing GIR)
- Triglycerides weekly if you're over 3 g/kg/day lipids
- Check prealbumin/transferrin every 1–2 weeks
- Get to enteral feeds ASAP (keeps the gut working)
- Reassess weekly as the kid improves or deteriorates